Sources close to the deal say that Microsoft will pay about $250 million for SwiftKey and that SwiftKey founders Jon Reynolds and Ben Medlock will pocket around $30 million each.

SwiftKey is available for Android and iOS devices, but not for Windows Phone–yet.

SwiftKey initially sold for $4, but became free in 2014. Its Android keyboard supports over 100 languages and the company developed a special language for the keyboard attached to acclaimed physicist Stephen Hawking’s wheelchair.

The London-based SwiftKey has more than 150 employees in London and many are expected to join Microsoft Reseach, sources said.